I need to permanently place some flat head bolts on the underside of a case panel. The goal is to have the 4 bolts anchor a 120 mm fan in place (with grill) so that there are no visible bolts on the ...

Actually, it seems to be a composite material, not sure if it's plastic. Someone was a bit too heavy for a chair here at work and cracked the seat. It's a $1200.00 chair, so I saved it from the trash.